Hi Jan-Erik,

The real confusing thing about all of this is that if one follows the advice
in the data sheet regarding refreshing the EEPROM, one appears to be
violating parameter D120 (ED) which is the cell endurance -- which is 10X
less than parameter D124 (TREF).

In other words, once you get to the point where you need to refresh the
EEPROM according to the D124 spec, you've already spent your endurance
budget! At least that's the way I see it. See below for more details:


(I'm specifically referring to the PIC18FXX2 data sheet (DS39564B) on page
268)


D120 (ED) - Cell Endurance:
---------------------------
100,000 erase/write cycles minimum, 1,000,000 erase/write cycles typical
(conditions: -40 deg C to +85 deg C)


D124 (TREF) - Number of Total Erase/Write cycles before refresh:
----------------------------------------------------------------
1 million minimum, 10 million typical.
(conditions: -40 deg C to +85 deg C)


Data EEPROM endurance and refreshing is not currently something I need to
worry about, but I'll probably see if I can get all of this clarified with
Microchip. Changing the subject back to the EEPROM refreshing
recommendation, I'm wondering if this applies to the older parts that have
data EEPROM like the PIC16F877, since there is no mention of EEPROM
refreshing in the PIC16F87X data sheet DS30292C.


Best regards,

Ken Pergola

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